PREVENTION OF BLOOD-LOSS IN DIALYZERS WITH DEAE CELLULOSE MEMBRANES DOES NOT REQUIRE INCREASED DOSES OF HEPARIN

Binding of heparin to DEAE-cellulose membranes may reduce bioavailable heparin, thus increasing the amount of heparin needed for anticoagula tion during dialysis. To test this hypothesis, blood loss and coagulat ion were evaluated during dialysis with DEAE-cellulose and polysulphon e membranes. The heparin dose required to effect a given increase in t he baseline recalcified activated clotting time (RACT) was determined using a pharmacokinetic model. Blood remaining in the dialyser post-di alysis (RBV) was measured by red cell lysis and haemoglobinometry. Pla sma thrombin-antithrombin III complex (TAT) was used to assess activat ion of the coagulation system. RBV and changes in TAT were determined in two crossover studies. Firstly, DEAE-cellulose membranes were used at doses of heparin calculated to increase baseline RACT by 12.5% and 25%. Secondly, DEAE-cellulose and polysulphone membranes were compared at a heparin dose calculated to increase baseline RACT by 15%. RBV fo r DEAE-cellulose membranes was independent of the dose of heparin and did not differ from that found for polysulphone membranes. TAT concent rations increased during dialysis; however, there was no difference be tween the two membranes. These results show that DEAE-cellulose membra nes do not require increased heparin to avoid dialyser-associated bloo d loss.